The count() method of the IDBObjectStore interface returns an IDBRequest object, and, in a separate thread, returns the total number of records that match the provided key or IDBKeyRange. If no arguments are provided, it returns the total number of records in the store.
Note: This feature is available in Web Workers.
Syntax
var request = ObjectStore.count(optionalKeyRange);
Parameters
- optionalKeyRange
- A key or
IDBKeyRangeobject that specifies a range of records you want to count.
Returns
An IDBRequest object on which subsequent events related to this operation are fired.
Exceptions
This method may raise a DOMException of one of the following types:
| Exception | Description |
|---|---|
InvalidStateError |
This IDBObjectStore has been deleted. |
TransactionInactiveError |
This IDBObjectStore's transaction is inactive. |
DataError |
The specified key or key range is invalid. |
Example
In this simple fragment we create a transaction, retrieve an object store, then count the number of records in the store using count() — when the success handler fires, we log the count value (an integer) to the console.
var transaction = db.transaction(['fThings'], 'readonly');
var objectStore = transaction.objectStore('fThings');
var countRequest = objectStore.count();
countRequest.onsuccess = function() {
console.log(countRequest.result);
}
Specification
| Specification | Status | Comment |
|---|---|---|
| Indexed Database API The definition of 'count()' in that specification. |
Editor's Draft |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|
| Basic support | 23webkit 24 |
10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
| Available in workers | (Yes) | 37.0 (37.0) | ? | (Yes) | ? |
| Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | 4.4 | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
| Available in workers | (Yes) | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase - Using transactions:
IDBTransaction - Setting a range of keys:
IDBKeyRange - Retrieving and making changes to your data:
IDBObjectStore - Using cursors:
IDBCursor - Reference example: To-do Notifications (view example live.)